Typewriting machine



Jan. 5, 1943. .1. F. SMATHERS 2,307,164

TYPEWRITING MACHINE Filed Oct. 15, 1940 ATTORNEY.

Patented Jan. 5, 1943 aim-1p STATES PATENT oF'FlcE mnwmmo MACHINE JamesF. Smathers, Rochester, N. Y., assignor to international BusinessMachines Corporation, New York, N. Y., a corporation of New YorkApplication October 15, 1940, Serial No. 361,208

2 Claims. (Cl. 197-35) This invention relates to typewriting machines.

The object of the present invention is to provide an improved type bar.

An object is to provide a type bar which is quieter in its operationthan type bars now used in the art.

An object is to provide a type member in which the type element ismovably mounted.

An object is to provide a type bar having a resilient construction inthe head.

Other objects of the invention will be pointed out in the followingdescription and claims and illustrated in the accompanying drawing,which discloses, by way of example, the principle of the invention andthe best modes, which have been contemplated, of applying thatprinciple.

In the drawing:

Fig. 1 is a side view of one form of the type bar.

Fig. 2 shows a modification.

In Fig. 1 there is shown a form of type bar which, it has been found, ismuch quieter than the usual type bars of present commercial machines.The type bars as now used in the art invariably consist of a solid blankof suitable shape to the end of which is secured a type element 5 havingupper and lower case characters 5a and 5b respectively. Such type barsare pivoted on the well known wire segment so as to swing in an arc ofapproximately 90 before striking the paper through the usual ribbon.Ordinary type bars are extremely noisy and efment 5 is in effectresiliently mounted on the end I of the type bar and is capable of avery limited yielding movement when the type strikes the paper throughthe ribbon.

The curved portion 4 extends to the left toward the opposite end of thetype bar to form the usual aligning lug B which cooperates with the typeguide to hold the type bar steady against lateral vibration at theprinting point. Near where the curved portion 4 joins the body of thetype bar, below the stop portion 3b, there is provided a collide lug Iwhich prevents defacing of the characters 5a, 5b in the event of acollision between two type bars. The type bar is also provided with along longitudinal slot 8, beginning near the center of the bar andextending close to the end of aligning lug 6 to give the type bargreater resiliency between the points where it strikes the anvil and thepaper, respectively. An anvil stop lug 9 is provided which strikes theusual anvil.

The type bar shown in Fig. 1 may be propelled by any well known meansbut is particularly well suited to power operated typewriters in whichthe type bars are operated by some form of power means and the keysmerely control the opforts to quiet them have not been completelysuccessful. Efiorts to quiet the type bar have been centered onproviding platens which have a tendency to absorb sound, as by providingthick soft rubber facings for the platen or a soft .rubber base for theplaten surface, or by modifying the internal structure of the platen.However, the problem cannot be solved by using a softer platen becauseit quiets the noise of the type bars at the expense of clear typeimpressions, the platen then being too soft and permitting the type barsto emboss the paper. With the present invention, an ordinary hard platenor one with a medium surface may be used which is hard enough to give aclear impression.

As shown in Fig. 1, the head of type bar 3 is formed with a bulbous slot3a to produce a reversely curved resilient portion 4 to which is securedthe type element 5, as by soldering in the usual way. The curved portion4, adjacent the left hand character 5b of the type element 5, is spacedfrom a stop portion 3b, formed in the head of the type bar, by a gap 4awhich may be between .005" and .010", whereby the type eleeration of thepower means. An example of such a machine is the well known Electromatictypewriter, which has also been known as the International. In poweroperated typewriters, the force of the blow exerted by the type bars isconsiderably greater than in manual machines, consequently, the noise isvery distracting when the type bars and platens commonly employed in theart are used.

When the type bar 3 is close to the printing point, the anvil lug 9strikes the anvil before the type characters 5a or 5b strike the ribbon.Thereafter the slotted end of the type bar flexes between the anvil lug9 and the platen suinciently to allow the type element to strike with awhipping action which insures a clear sharp impression of the charactersthrough the ribbon. After the type bar 3 strikes the anvil, the typecharacter or 5b is obstructed by the platen, and then the kinetic energyof the type bar causes the gap 411 between the curved portion 4 and thestop portion 3b of the type bar to close.

As a result of the provision of the gap 4a, it has been found that thetype bar actually is very much quieter than type bars most commonlyused, owing, apparently to the fact that the final impression force isby a spring action through the resiliently curved portion 4 rather thanby a solid blow. .Due to the small size of the gap and the resiliency ofthe curved portion 4!, no noise. results from the closing or the gapbut, nevertheless, there is sumcient spring pressure to quiet the blowand produce an even impression.

In Fig. 2 there is shown a modified form which operates upon the sameprinciple but in this case, the curved portion at Fig. i. which is freeat one end, is replaced by a curved resilient bridge portion It). Thisresilient bridge portion IE3 is formed by a. continuation 8a of the slot8 to the head of the type bar behind type element 5 so that the slot a,with the hook-shaped extension 80., is hooked or C-shaped to givemaximum resiliency to the bridge portion iii. The extension 80. of slot8 is constricted or reduced in width immediately behind the type element5 to form a stop gap for the stop 312. Thus the type element 5 isresiliently supported at both ends instead of at only one end, wherebythe type element 5 of Fig. 2 can yield in more nearly a straight lineinstead of moving in an are as in Fig. i.

In blanking both of the above type bars, sufficient metal is leftadjacent the stop portion 3a to insure suificient kinetic energy toclose the gap when the type element strikes. The gap in Fig. 2 may bethe same in dimension as in Fig. 1.

While there has been shown and described and pointed out thefundamentalnovel features of V gitudinal slot extending from the anvil contact-,

ing portion of the type bar into the head of the type bar; said slotbeing formed hook-shaped adjacent the type element and curving away fromthe type element to provide a curved resilient bridge in the head tosupport the type element, said slot also being constricted behind thetype element to form a gap which is closed upon impact of the typeelement.

2. A. type bar having a head, a type element, an anvil contactingportion intermediate its ends. and a type element supporting portion atone end; said type supporting portion being part of a curved bridgeformed by a curved slotwhich extends from a point substantially close tothe anvil contacting portion and into the head and is reversely curvedbehind the head toward the anvil contacting portion to provide a highdegree of resiliency in the type supporting portion, said slot beingconstricted adjacent the type element

